Recent years have witnessed ever increasing quantities of carbonated beverages, such as beer and carbonated soft drinks, being packaged in amounts of up to 12 ounces in metal cans and particularly in metal cans with ends that include a score line defined opening panel therein to provide implement free access to the contents. Such opening panel containing can ends are generally called "easy open ends" and include variant basic constructions of a first type wherein the score line completely circumscribes the panel to render the panel completely separable from the can end and of a second type wherein the score line only partially circumscribes the panel to render the latter only partially severable from the can end and to thus remain in attached relation within the can after the pouring opening has been formed. Among the variant constructions of the second type are those that include a manually displaceable lever member to fracture the score line and to pivotally displace the hinged opening panel to a location within the can body, as exemplified by U.S. Pat. Nos. 4,024,981 and 4,148,410. Such variant constructions of the second type also include can ends in which the lever member is dispensed with and score line fracture and panel displacement is initiated by application of direct finger pressure on, or adjacent to, the score line, as exemplified by U.S. Pat. Nos. 3,929,251, 3,997,076 and 3,977,341. As mentioned above, all such opening panels are conventionally perimetrically delineated by score lines of decreased metal thickness.
In order to extend the use of such easy open can end constructions to larger volume containers, the art has suggested the utilization of a cap assembly to close and reseal the opening defined by such score line defined panel. Among the objects of such cap utilization are a re-closure of the container to prevent loss of liquid content and a resealing of the container to limit further losses of the dissociable gases, i.e., the "carbonation", in the remaining liquid content. U.S. Pat. No. 4,580,692 discloses one construction for such a resealable closure cap assembly in association with a selectively contoured can end construction to cooperatively accommodate such resealable closure and to retain the advantages characteristic of the "easy open end" constructions.
The provision of commercially acceptable resealable easy open can end constructions for larger capacity beverage containers requires both sealable retention of the can contents and accommodation of the inherent pressure buildup therein. Also required is a can end configuration at the pouring opening that dispenses with any lever mechanisms or the like and which is easily and readily opened by the user by mere application of finger pressure in a simple and non-hazardous manner, all without diminution of the convenience and cost effective nature of the basic easy open end constructions during manufacturing, filling, shipping, selling, and consumer usage thereof. As such, the provision of a commercially acceptable lever-free resealable easy open end construction requires accommodation of problems not heretofore met in the basic easy open end constructions conventionally employed in the smaller capacity beverage cans.
Experience to date with the resealable cap and can end construction disclosed in U.S. Pat. Nos. 4,580,692 and 4,648,528, the disclosure contents of which are herein generally incorporated by reference, has indicated that difficulties have been encountered by some users in both effecting optimum location of the point of finger pressure application relative to the score line defined opening panel and in the undue amounts of digital pressure required for effecting score line fracture and panel displacement particularly when such finger pressure is applied at locations other than the desired optimum location therefore.